The present invention relates to electric lights and, more particularly, to extremely long-life luminaires for illuminating exit signs, and related emergency signs and the like, which luminaires do not require retrofitting of the fixtures with which they are used.
The bulbs currently available for emergency light fixtures such as exit signs have, considering their intended use, short lives of the order of 300 to 2000 hours with, as would be expected, shorter lives for individual units within this group. The cost of constantly checking, maintaining, and replacing bulbs is estimated to be at least $100 per year per fixture for outside maintenance and $60 per year for in-house maintenance.
A related and more significant problem relating to these fixtures is the danger to humans if exit signs and the like are not illuminated due to burned-out bulbs and the exits in a burning or damaged building cannot be found. Deaths resulting from such occurrences are possible and in addition to human suffering there is the ever-present threat of expensive and protracted litigation.
There is a significant need for bulbs with extended life, say, on the average, five- to ten-year lives with a guaranteed three- to five-year life. The savings in lives, injuries, maintenance costs, damages, and lawsuits would be highly significant with the availability of such a bulb, particularly one that does not require retrofitting of existing fixtures. It is believed that this latter feature, although not essential to a successful product, is in fact significant.